1. Field of the Invention
This invention relates to a logic circuit using complementary type Metal Oxide Semiconductor Insulated Gate Field Effect Transistors (hereafter referred to CMOS transistors).
2. Description of the Prior Art
In LSI (Large Scale Integrated Circuit), the shortening of the response time from the input of the signal to its output is extremely important in conjunction with the fact that computers are being made large and with the development of a 1 chip CPU (Central Processing Unit) and the like. In particular, this is due to the fact that the increase in the amount of information calls for an increase in the processing capacity of the computers processing this information.
On the other hand, in addition to this requirement, it has become possible to incorporate large systems in 1 chip LSI and therefore these are being operated by dry cells or the like and are being made light in weight and compact. In order to operate with a dry cell, it is necessary that the electrical power consumed by the LSI should be made low. Now, these two requirements contain mutually incompatible matter. That is to say, to make the response of the elements faster for a certain load capacity, the electric currents may be made to flow in larger quantities, but this involves an increase in the electrical power consumed by the LSI. Therefore it is important to obtain high speed elements with low power consumption. To meet this requirement it is necessary to reduce the load capacity.
Now, as regards the load capacity in a MOS circuit, there is the gate capacity of the inverter circuit in the next stage, the aluminum or other wiring capacity, the diffusion capacity and the like, but here it is important to reduce the diffusion capacity because it is difficult to reduce the gate capacity and the wiring capacity. In the SOS (Silicon On Sapphire) technique the diffusion junction area is reduced whereby reduction of the abovementioned diffusion capacity is achieved. However in the SOS technique, the manufacturing process is very complicated and is difficult to practice.